In general, building panels for interior and exterior walls or ceilings of buildings are formed of incombustible materials that do not release toxic gases when a fire breaks out. One of typical incombustible panels is a gypsum panel.
The gypsum panel may be classified into a board type and a tile type. The board type gypsum panel is used together with a finishing material such as paints or wallpaper. On the other hand, the tile type gypsum panel is used together with a finished tile.
Recently, attempts have been made to impart sound-absorbing performance to such a gypsum panel.
Gypsum panels having sound-absorbing properties can be divided into three types. The first type is a porous type made of glass, wool, rock wool, or vegetable fibers, the second type is a plate vibration type made of fiber plates or gypsum boards, and the third type is a resonator type made of gypsum cement having a plurality of holes and having excellent sound-absorbing properties at a specific frequency.
Among these gypsum panels, as domestic gypsum panels currently used in practice, the gypsum panel made of gypsum cement having holes is partly used, and the gypsum panel having a porous structure using rock wool is mainly used.
The gypsum panel made of gypsum cement having holes has an advantage in that sound-absorbing properties are excellent, and a problem in that it is difficult to clean when used for a long period of time due to contamination of the holes.
On the other hand, the gypsum panel having a porous structure using rock wool is fragile due to poor strength as compared with the gypsum panel made of gypsum cement having holes, and its sound-absorbing frequency band is mainly a high frequency band of 1,000 Hz or more. As such, this gypsum panel does not selectively absorb sound waves at a low frequency band of 200 Hz to 1,600 Hz at which absorption of sound is actually required.